Maria Grazia Piancino1, Deborah Falla2, Andrea Merlo3, Teresa Vallelonga4, Corrado de Biase5, Domenico Dalessandri6, Cesare Debernardi7. 1. CIR Dental School, Department of Surgical Sciences, Division of Orthodontics, University of Turin, Italy. Electronic address: mpiancin@unito.it. 2. Department of Neurorehabilitation Engineering, University Hospital Gottingen, Germany. Electronic address: deborah.falla@bccn.unigoettingen.de. 3. Motion Analysis Laboratory, Local Health Unit (AUSL) of Reggio Emilia, Department of Rehabilitation, Correggio, Italy. Electronic address: andrea.merlo@ausl.re.it. 4. CIR Dental School, Department of Surgical Sciences, Division of Orthodontics, University of Turin, Italy. Electronic address: vtitty79@libero.it. 5. CIR Dental School, Department of Surgical Sciences, Division of Orthodontics, University of Turin, Italy. Electronic address: cdebiase@unito.it. 6. School of Dentistry, Division of Orthodontics, University of Brescia, Italy. Electronic address: dalessandridomenico@libero.it. 7. CIR Dental School, Department of Surgical Sciences, Division of Orthodontics, University of Turin, Italy. Electronic address: cesare.debernardi@unito.it.
Abstract
OBJECTIVE: To describe the effects of therapy on masseter activity and chewing kinematic in patients with unilateral posterior crossbite (UPC). DESIGN: Fifty children (age: mean ± SD: 9.1 ± 2.3 years) with UPC (34 on the right side, 16 on the left side) and twenty children (age: 9.5 ± 2.6 years) with normal occlusion were selected for the study. The mandibular motion and the muscular activity during chewing soft and hard boli were simultaneously recorded, before and after correction with function generating bite, after a mean treatment time of 7.3 ± 2.4 months plus the retention time of 5-6 months. The percentage of reverse cycles and the percent difference between ipsilateral and contralateral peaks of the masseter electromyography envelopes were computed. RESULTS: Before therapy, the percentage of reverse cycles during chewing on the crossbite side was greater in patients than in controls (P<0.001) and significantly reduced after therapy (P<0.001) towards the reference normal value (soft bolus; pre: 57 ± 30%, post:12 ± 17%; hard bolus; pre: 65 ± 34%, post: 12 ± 13%; reference value: soft bolus 4 ± 2%, hard bolus 5 ± 3%). Before therapy the percent difference between electromyography envelope peaks in patients was lower than in controls (P<0.01) and significantly increased after therapy (P<0.05) becoming similar to the reference normal value. CONCLUSIONS: The correction induced a normal-like coordination of masseter muscles activity together with a significant reduction of the reverse chewing patterns. The previous altered muscular activation corresponded to the altered kinematics of reverse chewing cycles that might be considered a useful indicator of the severity of the masticatory function involvement.
OBJECTIVE: To describe the effects of therapy on masseter activity and chewing kinematic in patients with unilateral posterior crossbite (UPC). DESIGN: Fifty children (age: mean ± SD: 9.1 ± 2.3 years) with UPC (34 on the right side, 16 on the left side) and twenty children (age: 9.5 ± 2.6 years) with normal occlusion were selected for the study. The mandibular motion and the muscular activity during chewing soft and hard boli were simultaneously recorded, before and after correction with function generating bite, after a mean treatment time of 7.3 ± 2.4 months plus the retention time of 5-6 months. The percentage of reverse cycles and the percent difference between ipsilateral and contralateral peaks of the masseter electromyography envelopes were computed. RESULTS: Before therapy, the percentage of reverse cycles during chewing on the crossbite side was greater in patients than in controls (P<0.001) and significantly reduced after therapy (P<0.001) towards the reference normal value (soft bolus; pre: 57 ± 30%, post:12 ± 17%; hard bolus; pre: 65 ± 34%, post: 12 ± 13%; reference value: soft bolus 4 ± 2%, hard bolus 5 ± 3%). Before therapy the percent difference between electromyography envelope peaks in patients was lower than in controls (P<0.01) and significantly increased after therapy (P<0.05) becoming similar to the reference normal value. CONCLUSIONS: The correction induced a normal-like coordination of masseter muscles activity together with a significant reduction of the reverse chewing patterns. The previous altered muscular activation corresponded to the altered kinematics of reverse chewing cycles that might be considered a useful indicator of the severity of the masticatory function involvement.
Authors: Andrea Viggiano; Sara Ponticorvo; Antonietta Canna; Carmine Secondulfo; Ludovico Sbordone; Antonio Russo; Marcellino Monda; Francesco Di Salle; Fabrizio Esposito Journal: Front Syst Neurosci Date: 2021-02-26